Single bath zirconium coating: a greener and smarter industrial surface treatment

• H. Gokdag and A. Cetin

Tnh Chemistry R&D Central, 10026 Sokak No: 6, AOSB, 35620 Çiğli, İzmir, Turkey

Abstract: This study introduces a novel single bath zirconium based nano conversion coating system that integrates both degreasing and surface treatment in a single step eliminating the need for traditional pre-cleaning and multi-stage conversion baths. While zirconium conversion coatings have gained attention as environmentally friendly alternatives to phosphate systems, most implementations in the literature still rely on a separate alkaline degreasing stage, thereby limiting their sustainability and process efficiency advantages. The proposed integrated method addresses this critical gap by offering a fully consolidated pretreatment process, which reduces operational complexity and environmental impact. The system was evaluated on steel substrates and benchmarked against a commercial nano-phosphating process through standardized corrosion resistance (ASTM B117, ISO 4628-3/8), paint adhesion (ISO 2409), and impact resistance (ISO 6272-1) tests. Additional surface characterization was conducted using SEM and EDX techniques. Results demonstrated that the single-bath zirconium system provides superior corrosion protection, improved paint adhesion, and comparable mechanical performance, while achieving substantial reductions in chemical usage (–89%), water consumption (–80%), and energy demand (–100%). Furthermore, it eliminates phosphate sludge waste entirely. By demonstrating–for the first time–a truly integrated zirconium-based surface pretreatment, this work fills a major gap in the literature and positions the technology as a viable, sustainable replacement for conventional phosphating lines.

Keywords: zirconium, single bath coating, phosphate coating, degreasing, nano coating, corrosion, salt fog test, adhesion

Int. J. Corros. Scale Inhib., 2025, 14, no. 3, 1605-1621
doi: 10.17675/2305-6894-2025-14-3-29

Download PDF (Total downloads: 25)

Back to this issue content: 2025, Vol. 14, Issue 3 (pp. 1018-1684)